(1) Field of the Invention
The present invention relates generally to power supply systems, and more particularly to power supply systems for high repetition rate pulse discharge driven systems.
(2) Description of the Prior Art
A large ampere current pulse that is a requirement of pulse discharge driven systems, is often realized through a capacitor that is charged to a certain voltage and discharged at a specified time to deliver the energy required of the pulse discharge driven system. Examples of pulse discharge driven systems include Doppler radar and lasers. In these systems, it is necessary to deliver the energy from the capacitor to the system in a precise manner, wherein the precision relates to the timing of energy delivered, and the amount of energy delivered. For instance, in a Doppler radar system, it is necessary to deliver the same energy each pulse repetition interval to allow the return signals to be properly processed, as fluctuations in the delivered energy may cause variability in the transmitted pulses that are then misinterpreted by the receiver. Similarly, a laser system requires the same precision in timing and energy for proper laser operation, as there is a nonlinear relationship between the energy delivered and the laser performance.
Prior art power supply systems utilize peaking capacitors in magnetic pulse compression circuits to provide a repetitive, high voltage, high energy charge to a peaking capacitor in a short duration. In such systems, multistage LC networks typically convert long, relatively low voltage pulses into the desired short, high voltage pulses. Other prior art systems include pulse power supply systems that supply excimer lasers with high voltage, short pulses. The majority of the prior art systems, however, operate in the 1000 Hz range. One prior art system operating at higher frequencies does not allow asynchronous operation, as the power supply system operation is coordinated precisely with the pulse discharge driven system. In that prior art system, the timing between the pulse discharge driven system and the charging capacitor reaching a specified voltage, must be synchronized precisely, as the problem of maintaining a specified voltage across a capacitor is well-known.
There is not currently an asynchronous power supply system for pulse discharge driven systems, wherein the power supply system may operate at higher repetition frequencies and not require synchronous coordination with the pulse discharge system.
What is needed is an efficient power supply system to accurately operate at higher pulse rates, wherein the power supply system may operate asynchronously with respect to the pulse discharge driven system.
It is an aspect of the invention to provide a power supply system that supplies electrical pulses to a pulse discharge driven system. In one aspect of the invention, the power supply system includes a pulse generating circuit with a charging inductor and a charging capacitor, wherein the charging capacitor drives the pulse discharge driven system. It is another aspect of the invention to select the charging inductor to achieve a time constant that is coordinated with the pulse rate of the pulse discharge driven system.
In one embodiment, the pulse generating circuit further includes a, xe2x80x9ckeep upxe2x80x9d high-voltage power supply, three solid-state switches, and a diode. The voltage across capacitor is initially charged through the main power supply, wherein the time to charge the capacitor is determined in part by the charging inductor value. The capacitor voltage is monitored and compared to a predetermined xe2x80x9ccontrolxe2x80x9d voltage that is less than a xe2x80x9cdrivingxe2x80x9d capacitor voltage that satisfies the requirements of the pulse charge driven system. Upon the capacitor voltage attaining the control voltage, a control module commands a solid-state switch to disconnect the main power supply from the circuit, thereby resulting in a sourceless (R)LC circuit that allows the capacitor to continue charging at a more controlled rate through the inductor discharge. Once the capacitor charges to the driving voltage, the control module commands two solid-state switches to separate the inductor from the capacitor, and similarly, the control module commands the keep-up supply to monitor and maintain the capacitor charge. If the capacitor discharges before the pulse discharge system utilizes the capacitor charge, the keep-up power supply replenishes the capacitor charge to the driving voltage.
It is another aspect of the invention that when the capacitor is discharged by the pulse discharge system, the control module returns the pulse generating circuit to its original state, incorporating the main power supply and inductor by returning the solid-state switches to their original states.
It is another aspect of the invention to supply power to a pulse discharge driven system, wherein the pulse discharge driven system is a laser.
Other objects and advantages of the invention will become obvious hereinafter in the specification and drawings.